Clock Steering Using Frequency Estimates from Stand-alone GPS Receiver Carrier Phase Observations

摘要

Carrier phase observations from a stand-alone GPS receiver are used to estimate the frequency of a clock for the purpose of steering it to GPS System Time. Utilization of this frequency estimate can significantly improve the frequency stability performance of a class of timing systems where an oven controlled crystal oscillator is disciplined by GPS time difference estimates. In these systems, the frequency difference estimates are more stable than both the local oscillator and the GPS clock time difference estimates over intermediate time intervals. Oscillator disciplining using these frequency difference estimates enables improved mid-term frequency stability without incurring the size, weight, and power costs of an atomic frequency reference.